Newbies Question: Do I really need to sacrifice Prefix-aggregation to do BGP Load-sharing?

Douglas Fischer fischerdouglas at
Thu Oct 20 12:51:14 UTC 2022

If your Upstream(Transit provider) prepends your routes without you asking
or authorizing it to do so, you should SERIOUSLY consider switching

In the other email I talked about traffic engineering BGP communities.
If those prepends were made from some community you were applying... OK,
that's great!
Even better if you could apply a community that did something like "apply 2
prepends for south america only".

But a Transit Provider changing the AS-PATH (in addition to the mandatory
hop) arbitrarily without your consent is not for good people.

P.S. Your email replies are breaking threads in email readers. I suggest
you review the email client tool.

Em qui., 20 de out. de 2022 às 09:16, Pirawat WATANAPONGSE via NANOG <
nanog at> escreveu:

> Dear all,
> Before all else:
> thank you all for the lightning-fast responses (even taking the time zone
> advantage into account).
> I really, really, really appreciate all your recommendations.
> Virtually all of you recommend prepending as the first choice.
> I also get the feeling that you guys consider de-aggregation “distasteful”
> (at the least) but sometimes unavoidable.
> I have considered the prepending myself, but dare not implement it yet
> for the fear that BGP (Human) Community will burn me alive, witch-hunt
> style,
> because of the following reasons:
> 1. I can see from looking glass(es) that my upstreams already practice
> prepending (some paths) at their level (at least 3 more hops [x4]),
> supposedly to “balance” their bandwidth.
> 2. Should I start prepending mine, I might upset their balance, causing
> them to prepend more, thus starting a “prepend war”. [I imagine that x20+
> prepending starts out this way]
> The way I see it, prepending (or maybe even the whole BGP-Path thing) is a
> local-optimization problem: it’s only best for someone, not globally.
> And the Higher-Tiers (Lower Tier-Numbers) will always “engineer” me in the
> end.
> Worse yet, I might be out-voted by de-aggregation insider “cultists”
> anyway.
> Which forces me to proactively ask you guys questions about
> ROV-Overlapping and ROV “Hijack Gap” soon, in another posting with separate
> “Subject:”.
> Again, Thank you.
> Cheers,
> Pirawat.
> P.S.  [Off-Topic] Any comment on the “SCION” System?
> Any good (I will even take "academically")?
> [Reference:]

Douglas Fernando Fischer
Engº de Controle e Automação
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